How can I tell if i might need a 16 amp supply?

[stuartpaul]

I'm in the market for a new P/T and looking at the Axminster AWEPT106 (also looking at the AW106PT2 but it's £175 more, - that'll pay for the new morticer ).

The blurb in the catalogue says that a 16 amp supply might be necessary if the voltage is 'on the low side' (whatever that means!).

So, - is there any way I can possibly tell before I buy that I might need such a supply (therefore erroding any possible saving over the PT2) without calling in a sparks and further erroding the savings?

I have got a spare way on the fuseboard so adding an additional circuit isn't going to be a major problem if I have to.

Yes, - I am tight when spending potential tool money!!

I'm an electrical dunce so any explanations in silly person proof language please.

 

[9fingers]

If your voltage is lower than normal then the motor will draw more current when starting. The blurb is being helpful and telling you like it is.
Is your voltage lower than normal? only you can tell - how can we help you?

My advice would be to buy the machine you want and upgrade the supply if you need to - if it does not blow fuses then that is a bonus.

Bob

 

[SemiSkilled]

http://www.axminster.co.uk/product-Axmi ... 580438.htm

In the spec it says the motor is rated a t 2.2 Kw or 2200 watts

Divide that by 240 so, 2200W / 240V = 9.16 Amps this would be the running load, sounds OK at that, under 13A for a plug top but

When you switch the motor on there is a large current rush to "Fill up the motor with magnetism" ( a bit more complicated than that but I won't go into it)

For a split second a motor could take approx 5 times the running current and that will blow a 13 A fuse.

To be reliable I'd use a 16A circuit

Lee.

 

[jonbikebod]

Tending to confirm what Lee and Bob have said, mine runs fine with a 13 amp plug/fuse fitted. It just so happens it is plugged in within feet of the consumer unit so the will be very little voltage drop and last time I checked I was getting bang-on 240V. in the workshop.
I tried this with an open mind, prepared to install a 16A feed if it was needed – blowing a plug fuse being the worst that would happen if it did. As the fuse hasn’t blown, that is how it stayed.
I would feel more comfortable with a 16A feed and will probably do that one day…
Jon.

 

[ike]

The commonsense and simplest approach is to attach a 13 amp plug and see how it goes. It may work fine* and then you've avoided any unneccesary expense. Having said that there is no reason why you can't replace an existing 13A outlet with, or add an additional 16A IEC type outlet to your existing ring main circuit in the workshop. A dedicated circuit though would be a 'better' arrangement if you have a spare breaker on your CU.

*The issue is with the fuse rating and generally not the cable (as long as you have min. 2.5mm2 wire on a ring circuit). But even if it appears to work, if on the limit, the high current can quickly degrade the fuse contacts and overheat the plug body.

Ike

 

[StevieB]

Before you go for that machine, have a read of the other recent thread running on PTs :

https://www.ukworkshop.co.uk/forums/viewtopic.php?t=22938

and do a forum search. The machine you are considering is a rebadged version of the perform PT which some members (myself included) have found to be less than ideal for quality results. After going to all the effort of getting one it would be a shame if it didnt live up to your expectations!

Steve.

 

[jonbikebod]

Prompted by StevieB I just checked the link and I went for the AW106PT – the more solid/expensive machine. It could be it has a more efficient motor in it which would be another reason go for that model.
Jon

 

[Mike.C]

SP after taking serious notice of what StevieB has said above. If you do go for any machine that is on the borderline of 16/13 amp, IMHO you would be better off going for a dedicated 16amp circuit. I know its extra money that you could be spending on tools, but in the long run it's certainly worth it, and I had a isolation switch fitted at the same time, so if you have any kids about its much safer.

Cheers

Mike

 

[Anonymous]

SP after taking serious notice of what StevieB has said above. If you do go for any machine that is on the borderline of 16/13 amp, IMHO you would be better off going for a dedicated 16amp circuit.Mike

This would be sound advice if a 2.2KW motor were on the borderline of 13/16A supplies. It isn't - unless there is some problem with the installation of your supply (see below).

I run a couple of machines with 2.2KW motors on 13A plug tops without any problems.

Although there can be a largish surge at startup, it is over a very short duration (especially as the actual physical load on the machine at startup is small), and it should not blow a 13A fuse. If the machine is sitting on a dodgy supply for some reason (old wiring, long cable runs, poor installation, under rated wires), then it may take out a circuit breaker at startup, but you can use motor rated protection instead.

As far as steady running is concerned, you will be fine and a 13A plug top are used in all houses on 3KW loads.


Connect the machine to a 13A plug top and see how it runs (likely to be fine).
If the breaker pops, then check all screws at terminals are tight (SWITCH MAINS OF FIRST) and look at a motor rated (Type C) breaker (designed to absorb the start up surge) http://www.tlc-direct.co.uk/Products/MK8706.html

 

[Anonymous]

For a split second a motor could take approx 5 times the running current and that will blow a 13 A fuse.

Lee.

Not likely that the fuse will blow, more likely that the cricuit breaker in the consumer unit will trip. Fuses take a long time to blow and MCBs typically take only 30mS or so

However, 13A plug tops are fine for 2.2KW motors in most cases unless the house wiring is problematic in some way

 

[Mike.C]

Tony wrote,

Mike.C wrote:
SP after taking serious notice of what StevieB has said above. If you do go for any machine that is on the borderline of 16/13 amp, IMHO you would be better off going for a dedicated 16amp circuit.Mike


This would be sound advice if a 2.2KW motor were on the borderline of 13/16A supplies. It isn't - unless there is some problem with the installation of your supply (see below).

Tony my point was that the machine that SP has mentioned seems to have a bad name with SOME members, and as for the borderline bit, what I mean is whatever machine he goes for (no size motor mentioned) if the power of the motor is on the borderline between 13 and 16amp, then IMHO I would go for the 16amp.

Cheers

Mike

 

[stuartpaul]

Thanks for all the responses.

I'm now not so concerned with the electrical issues but the standard of the proposed machine! I really don't want to invest in a bit of kit that I may well have problems with at a later date.

The AW106PT2 does now look as if it would be a much sounder bet as a machine that I'd be happier with in the longer term (and this is going to have to last me a while).

I'll be off to have a play at Axminster over the weekend and make a final decision.

 

[OPJ]

Yep, I'd also advise you (from personal experience!) to spend the extra £100 and go for the AW106PT - you really do get an awful lot more for your money and it's only 1,100w.

 

[Mike.C]

OPJ wrote,

Yep, I'd also advise you (from personal experience!) to spend the extra £100 and go for the AW106PT - you really do get an awful lot more for your money and it's only 1,100w.

Also I have a 3 blade block and the extra blade makes hell of a lot of difference :lol:

Cheers

Mike

 

[Digit]

However, 13A plug tops are fine for 2.2KW motors in most cases unless the house wiring is problematic in some way

Or you supply company don't want to know. On a good day my line at the consumer unit might make 220 volts and my saw will start on a 13 amp fuse.
On a bad day, winter evenings ets, I'll be lucky to get a reading that makes 200 volts, then the fuses leave faster than my daughter can empty my wallet!. Try the 13amp, if it works, great, if not, up grade.

Roy.

 

[TheTiddles]

I too was recently considering buying the same machine, the 16amp possibility was one of the many factors that persuaded me to buy the 106 machine which I am extremely pleased with. The thing I would point out is that the smaller machine is a small machine on a box, it's physically not much so doesn't have much weight etc... the larger machine has lots of steel to keep it still, a quiet efficient motor mounted low in the body and I have been running it on a standard 13A circuit in a house that has dodgy everything, so I'm assuming the electrics are dubious too, at the end of a 10m extension cable without any problems, for the sake of £100+ I would save up slightly longer and not compromise

Aidan

 

[tigerturnings]

If the breaker pops, then check all screws at terminals are tight (SWITCH MAINS OF FIRST) and look at a motor rated (Type C) breaker (designed to absorb the start up surge) http://www.tlc-direct.co.uk/Products/MK8706.html

This is probably a good solution but you should be aware that under Part P of the Building Regulations, works like this should be undertaken - or at least tested and inspected - by a suitably qualified competent person. I think the applicable standard is BS7671 (essentially the IEE Wiring Regulations under a new name)

One particular test for cases where a C type (motor) breaker is installed is to check that the Earth Fault Loop Impedance is within acceptable limits to ensure that the breaker will disconnect within a suitable time should a fault occur.

TT